2. 



DESCRIPTION OF PLATES. 1/3 



Plate 15. 

 Fig. I. A clavicle of right side, probably Dimetrodon, No. 1080 University of 



Chicago. X %. 

 Anterior cervical vertebrEC of Dirnetrodon masivus, No. looi University of 

 Chicago, a, the preatlantal intercentrum ; b, the atlas ; c, the second inter- 

 centrum ; d, the axis. The neural arches are in the position in which they 

 were found, but one is reversed to show the opposite side. X Yg. 



3. United ilium and pubis of a small specimen of Dirnetrodon incisivus, No. 181 



University of Chicago. X about %. 



4. Interclavicle oi Dirnetrodon sp., No. 105 1 University of Chicago. X V^. 



5. Scapula of left side of Dirnetrodon incisivus, No. looi University of 



Chicago. X %. 

 5a. Fragment of right scapula of same, showing the depth of the humeral cotylus. 



Plate 16. 



Fig. I. Lower side of the forefoot of Dirnetrodon incisivus, No. 1003 University of 

 Chicago. X I. 



2. Fragment of the spine of the fourteenth vertebra of Dirnetrodon incisivus. 



No. looi University of Chicago, showing the finely striate surface. X i. 



3. Outer side of neural arch of Dirnetrodon incisivus, No. 1002 University of 



Chicago. X I. 



4. Inner side of same. X i. 



5. Anterior view, face of atlas of Dirnetrodon incisivics. No. 1566 Am. Mus. Nat. 



Hist. X I. 



6. Posterior view of same. X i. 



7. Tibiale(astragalus)of Z'/;«f/-'Wt)w/«««w«, No. 4025 Am. Mus. Nat Hist. X i. 



8. Tibiale (astragalus) of Dirnetrodon dollovianus. No. 1836 Am. Mus. Nat. 



Hist. X I. 



9. Tibiale (astragalus) of (?) No. 2278 Am. Mus. Nat. Hist. X i. 

 10. Tibiale (astragalus) of (?) No. 4130-4 Am. Mus. Nat. Hist. X i. 



Plate 17. 



Fig. I. Skull oi Dirnetrodon gigas. No. 1002 University of Chicago. X nearly Yi. 



2. Explanatory figure of same. 



3. Lower view of the first two sacrals of same. X %. 



4. Anterior view of same. X */,. 



Plate 18. 

 Fig. I . Skull of Dirnetrodon gigas, No. 1002 University of Chicago, with the bones of the 

 left side of the face removed, showing the ethmoid, prevomers, etc. Slightly 

 larger than fig. i, plate 17. 

 2. Explanatory figure of same. 



Plate 19. 

 Restoration of skull of Dinutrodon gigas, No. 1002 University of Chicago. 



All figures X about ^. 



Fig. I. Lateral view. 



2. Lower view. 



3. Posterior view. 



4. Median section. 



